In permanent magnet electric motors, there is a desire to increase the utilization of magnetic flux produced by the permanent magnets. Improved utilization of the magnetic flux may provide improved torque of the electric motor using the same voltage and current. One way to increase the magnetic flux of a permanent magnet rotor is to decrease flux leakage through the bridge portion of the rotor, or the area between the permanent magnet and the outer diameter of the rotor.
Previous methods of manufacturing rotors having permanent magnets involved using thin laminates of soft magnetic material. Portions of the laminate were cut out so that when the laminates were assembled, the permanent magnets could be inserted through these cut out portions. The use of laminates required that a single material be used to form the support portion of the rotor. Magnetic flux could leak through the bridge material of the laminate.
Accordingly, a need exists for alternative permanent magnet rotors and methods of manufacturing the same.